Combine sliced bananas, sour cream, vanilla and toffee bits in a bowl.
In another bowl combine flour, baking powder, baking soda and salt.
In electric mixer cream butter and brown sugar together until smooth.
Beat in eggs one at a time to butter and sugar mixture. Continue to beat for additional 2 minutes.
Add dry ingredients 1 cup at a time beating on low until fully mixed.
Fold in the banana mixture.
Add finished mixture into a greased 9×5 greased loaf pan.
Bake approximately 60 minutes. The top of the bread should be golden brown and the sides should be pulling away from the pan when it is done. Cool on a wire rack for 30 minutes.